Carney complex

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Carney complex is a disorder that is characterized by changes in skin coloring (pigmentation) and an increased risk of tumors. Many of the signs and symptoms of Carney complex become apparent during adolescence or early adulthood.

Almost all people with Carney complex have areas of unusual skin pigmentation. Brown or black skin spots called lentigines may appear anywhere on the body, but they tend to occur around the lips, eyes, or genitalia. In addition, some affected individuals have at least one blue-black mole called a blue nevus.

People with Carney complex have an increased risk of developing noncancerous (benign) tumors called myxomas in the heart (cardiac myxoma), skin, breast, and other parts of the body. Cardiac myxomas may be found in one or more chambers of the heart. These tumors can block the flow of blood through the heart, which can cause serious complications, including sudden death. Skin myxomas appear as small bumps on the surface of the skin or as lumps underneath the skin. In people with Carney complex, myxomas tend to recur after they are removed.

Individuals with Carney complex may also develop tumors in hormone-producing (endocrine) glands, such as the adrenal glands located on top of each kidney. Approximately 25 percent of people with Carney complex develop a specific type of adrenal tumor called primary pigmented nodular adrenocortical disease (PPNAD). PPNAD causes the adrenal glands to produce too much of the hormone cortisol. High levels of cortisol can lead to the development of Cushing syndrome, which is characterized by weight gain in the face and upper body, slow growth in children, bone loss, fragile skin, fatigue, and other health problems.

Tumors of other endocrine tissues, such as the thyroid, testes, and ovaries, are also seen in people with Carney complex. Many affected individuals have tumors on the thyroid gland called adenomas. Occasionally, people with thyroid adenomas develop thyroid cancer.

In people with Carney complex, adenomas may also form in the pituitary gland, which is located at the base of the brain. A pituitary adenoma usually causes the production of too much growth hormone. Excess growth hormone can lead to a condition called acromegaly, which is characterized by large hands and feet, arthritis, and distinctive facial features that are often described as "coarse."

Approximately 10 percent of people with Carney complex develop a rare tumor called psammomatous melanotic schwannoma (PMS). This tumor occurs in specialized cells called Schwann cells that wrap around and insulate nerve cells. These tumors are usually benign, but they can become cancerous (malignant).

Although most tumors that develop in people with Carney complex are benign, some affected individuals develop cancer over time. Complications associated with cardiac myxomas, PMS, or cancer can shorten the life expectancy for some affected individuals.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Variants (also called mutations) in the PRKAR1A gene cause most cases of Carney complex. This gene provides instructions for making one part (subunit) of an enzyme called protein kinase A, which promotes cell growth and division (proliferation). The subunit produced from the PRKAR1A gene helps control whether protein kinase A is turned on or off.

The variants in the PRKAR1A gene that cause Carney complex reduce the number of functional regulatory subunits that are available to protein kinase A. This causes protein kinase A to be turned on more often than normal, which leads to uncontrolled cell proliferation. The signs and symptoms of Carney complex are related to the unregulated growth of cells in many parts of the body.

Some individuals with Carney complex do not appear to have a variant in the PRKAR1A gene. In some of these cases, the disorder has been associated with a specific region on the short (p) arm of chromosome 2 called 2p16. Variants in other genes appear to play a role in a few cases of Carney complex. Researchers are working to discover additional genetic factors that can cause this condition.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Carney complex is typically inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Approximately 30 percent of Carney complex cases result from new (de novo) variants in the gene that occur during the formation of reproductive cells (eggs or sperm) in an affected individual's parent or during early embryonic development. These affected individuals typically have no history of the disorder in their family.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Carney complex is a rare disorder, although the exact prevalence is unknown. At least 750 affected individuals have been reported in the medical literature. Because Carney complex is rare and the features seen in affected individuals can vary, diagnosis of the condition may be delayed.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Pigmented micronodular adrenocortical disease · Very frequent (99-80%)

Blue nevus · Frequent (79-30%)

A solitary, bluish, smooth surfaced macule, papule or plaque that is generally round or oval in shape. The histopathology of blue nevi varies by subtype, but general characteristics include a vertical wedge or bulbous shaped proliferation of spindle cells, dendritic melanocytes, and melanophages into a sclerotic dermis or subcutis.

Cardiac myxoma · Frequent (79-30%)

A myxoma (tumor of primitive connective tissue) of the heart. Cardiac myxomas consist of stellate to plump, cytologically bland mesenchymal cells set in a myxoid stroma. Cardiac myxomas are of endocardial origin and general project from the endocardium into a cardiac chamber.

Cutaneous myxoma · Frequent (79-30%)

A myxoma originating in the skin.

Elevated circulating growth hormone concentration · Frequent (79-30%)

Acromegaly is a condition resulting from overproduction of growth hormone by the pituitary gland in persons with closed epiphyses, and consists chiefly in the enlargement of the distal parts of the body. The circumference of the skull increases, the nose becomes broad, the tongue becomes enlarged, the facial features become coarsened, the mandible grows excessively, and the teeth become separated. The fingers and toes grow chiefly in thickness.

Gonadal neoplasm · Frequent (79-30%)

A tumor (abnormal growth of tissue) of a gonad.

Increased circulating cortisol level · Frequent (79-30%)

Overproduction of the hormone of cortisol by the adrenal cortex, resulting in a characteristic combination of clinical symptoms termed Cushing syndrome, with truncal obesity, a round, full face, striae atrophicae and acne, muscle weakness, and other features.

Increased circulating insulin-like growth factor 1 concentration · Frequent (79-30%)

The concentration of insulin-like growth factor 1 (IGF1) in the blood circulation is above the upper limit of normal.

Other findings in the same source

From: Orphanet

Additional reported features include Increased circulating prolactin concentration (Frequent (79-30%)); Multiple cafe-au-lait spots (Frequent (79-30%)); Multiple lentigines (Frequent (79-30%)); Ovarian cyst (Frequent (79-30%)); Pituitary growth hormone cell adenoma (Frequent (79-30%)); Sertoli cell neoplasm (Frequent (79-30%)); Testicular neoplasm (Frequent (79-30%)); Atypical nevi in non-sun exposed areas (Frequent (79-30%)); Euthyroid multinodular goiter (Frequent (79-30%)); Spotty hyperpigmentation (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Carney complex is Endocrinology, with a endocrinologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which hormone or metabolic finding is important in this case?
• How should test timing and current medicines be taken into account?
• What follow-up would show whether the care plan is working?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Carney complex. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.